The present invention relates to a curable composition at room temperature having improved adhesion. More particularly, the present invention relates to a curable composition at room temperature having improved adhesion to films of coatings ordinary used such as melamine alkyd resin coatings and melamineacrylic resin coatings, which is suitable for use as an automotive refinishing paint.
It has been known that a hydrolyzable silyl group-containing vinyl resin is curable at room temperature due to moisture in atmosphere to form a fine network structure, thus resulting in formation of coatings having excellent gloss, weatherability, discoloration resistance, solvent resistance, hardness and adhesion to inorganic substrates.
Therefore, it is possible to use the hydrolyzable silyl group-containing vinyl resin in various purpose such as paints, adhesives, coating materials, sealants or binders, by utilizing such excellent properties of the resin.
However, the hydrolyzable silyl group-containing vinyl resin is unsatisfactory in adhesion to organic substrates. An automotive refinishing paint is required to have excellent adhesion to various coating films conventionally used, particularly to melamine-acrylic resin coatings or melamine alkyd resin coatings.
In order to improve the adhesion of the hydrolyzable silyl group-containing vinyl resin to the melamine alkyd resin coatings or melamine-acrylic resin coatings, there is known a method in which an amine silane coupling agent or a modified amine silane coupling agent is admixed with the resin. However, there are problems in the method such that the hydrolyzable silyl group-containing vinyl resin declines in storage stability and discoloring is easily caused.
An object of the present invention is to provide a composition curable at room temperature having excellent adhesion to the melamine alkyd resin coatings or melamine-acrylic resin coatings.
This and other objects of the present invention will become apparent from the description hereinafter.